1. Field of the Invention
The present invention is directed to a chemistry monitor system for a power plant that selects the most valuable next sample and, more particularly, to a system that uses the usefulness of the samples to control which chemistry monitors analyze the next sample and the source of the sample.
2. Description of the Related Art
Correct water and steam chemistry is critical to the prevention of corrosion in steam driven power plants. A number of locations around the steam cycle must be sampled and analyzed to know that the chemistry is correct and to understand why chemistry imbalances occur. Current practice varies from a minimum of a daily collection of samples from a few locations and manual analysis of a few chemical properties of the samples to a maximum of dedicated on line monitors for every possible chemical being analyzed and at every location or source from which samples are taken. The dedicated monitors are frequently supplemented by manual analysis of chemical species for which on-line monitors are not available. The daily collection of samples does not allow a sufficiently rapid adjustment of plant chemistry to prevent corrosion problems from occurring. The use of the maximum number of dedicated monitors is very expensive in all but the very largest and most efficient power plants. When a chemical imbalance occurs, manual analysis in all cases is increased in frequency and in the variety of chemical species for which amounts are determined In addition, during an imbalance, samples from special sample locations may be collected to specifically analyze the problem so that corrective action may be taken. U.S. Pat. No. 4,414,858 describes a valving system where samples from multiple streams are directed to an analyzer on a periodic fixed schedule basis by a computer.